so i have a 2001 dodge caravan sport, 3.3l v6 2wd, i wish to know what the rating of fuel the van need, what its recommened is, also my dad owns a 2002 dodge dakota 4.7 or 4.8 v8, forgot the exact engine, but what fuel would his truck need/recommend, please and thank you, also what are the ac psi recommendations, dakota already has ac, and my vans clutch dead and what would the van need to be at, thank you

 

Fuel requirements are normally stated on the fuel cap and in the owners manual. But, regular 87 octane pump gas is perfectly fine. No need to run anything else unless you are tuned. The Dakota is a 4.7. Have you checked the pressures yet on the AC system? Have you tried jumping the high pressure switch to make the compressor engage? If it's truly low, you have a leak. Need to fix that first. I recommend taking it to a shop that does AC work and get it looked at.

 

Octane increase means that the fuel takes more energy to initialize a combustion. If an engine has a higher compression, the temperature is running high, or you are driving near sea level the manufacturer might recommend 89 or 93 octane. If you have 8:1 to 10:1 compression (most naturally aspirated vehicles) then you would use 87; but I've heard (on NPR's Car Talk) that if you live in Denver or the like you can buy 85 octane for the same vehicle. The 3.6L in my 2018 has 11:1 compression and runs about 205°F, it can use 87 octane and even perform well climbing a hill and not have any knocks (knock being made by exploding gas when the piston is coming up and before spark). However if I run 89octane I seem to get 1mpg better in a similar temperature outside but I don't have enough data to know it's the fuel or just where I happened to drive during that tank.

I do know though that when I use Torque android app on my phone connected to my van through OBDII I see that running 87octane the timing is advanced to the mid 30's and running 89octane it is advanced about 15 to 25. The app doesn't give me units but I believe those numbers are degrees. I've never set timing on a car before so I'm not entirely sure what that all means.